1. Field of the Invention
The present invention relates generally to a telecommunications system for originating calls using a hardwire connection that bypasses and thus does not require the involvement of a local service provider with respect to vertical and call control features and functions and, in particular, to such a system that uses analog in-band signaling without requiring specialized customer premises equipment.
2. Description of the Prior Art
Prior art systems for originating and receiving telephone calls, particularly long distance telephone calls, typically involve routing through the facilities (e.g., switches) of a local service provider, commonly called a local exchange carrier (LEC). With respect to outgoing calls placed from a subscriber location, the LEC switch serving the subscriber""s customer premises equipment senses an off-hook condition and extends dial tone. When the dialed digits are received in the LEC switch, any features associated with the originating subscriber, such as speed dialing, are applied to the call, and the call is then routed to the desired destination. If the call is a long distance call that is routed to a long distance or inter-exchange carrier (IXC), then the IXC will pay originating end and terminating end xe2x80x9caccess chargesxe2x80x9d to the LEC for servicing the call, and the subscriber will, in turn, pay the IXC for the call.
Currently, the access charges paid to LECs by the IXCs for the use of carrier common line service vary by LEC but can, depending on a call""s duration and cost per minute, constitute upwards of 40% of the overall cost of the call. Accordingly, eliminating the cost of the originating end access charges could save a significant percentage of the cost of a long distance call. Bypassing the LEC and the associated originating end access charges could save the IXCs a significant portion of their service costs for providing long distance calls and, once the associated savings are passed on to the subscribers, potentially save the subscribers billions of dollars each year in long distance charges. Payment of such access charges remains a thorny issue in the competitive environment in the telecommunications industry since the passage of the recent telecommunications legislation and is a primary obstacle to enhanced competition between the LECs and other potential entrants into the local telecommunications marketplace. As a result, any long distance service provider who can bypass the LEC and avoid payment of the originating end access charges will be at a substantial competitive advantage.
The inventor is aware of three prior art techniques by which to complete a long distance call without paying the access charges to the LEC.
The first prior art technique known to the inventor for bypassing the LEC is to provide a separate communications system which provides the subscriber with access to the unregulated long distance telephone carriers through an alternative transmission path besides telephone lines into the subscriber""s premises. For example, Baran describes in U.S. Pat. No. 5,550,820 a bi-directional communications system which bypasses the LEC by conveying voice and data over cable television lines from the customer premises to a switching unit that has the functionality of a Class 5 central telephone office switch and is connected to the public switched telephone network. In the system described by Baran, special terminal units are provided at the customer premises, and the signals from the terminal units are converted by a relay transceiver bi-directionally between the signal format of the terminal units and fixed length compliant asynchronous transfer mode (xe2x80x9cATMxe2x80x9d) cells. These ATM cells are then transmitted via the cable television bandwidth to a cable television hub where the ATM cells are bi-directionally converted by a transmission interface unit into time division multiplexed signals in the upstream direction away from the terminal units for connection to a cellular telephone switch, and from time division multiplexed signals into fixed length compliant ATM cells in the downstream direction towards the terminal units.
While the system described by Baran does indeed bypass the LEC, it still encumbers the subscriber and long distance carrier with many of the same problems as the conventional telephone system. In particular, since the cable television lines are typically owned and operated by a cable television company, access charges are still payable to the cable television company. Also, additional equipment, namely, the terminal units, are required at the customer premises, leading ultimately to additional cost to the subscriber.
The second prior art technique known to the inventor for bypassing the LEC is to create a virtual piped connection over the conventional telephone lines using specialized customer premises equipment at the subscriber location and a specially configured call control platform in the IXC network to originate and receive calls using in-band signaling techniques. Such a technique is described in U.S. Pat. No. 5,533,111, where Schlanger describes a system utilizing a specialized multiplexer to create a virtual piped connection by converting an analog trunk signal into a usable in-band digital carrier. The virtual pipe is established through an initial call made from the specialized customer premises equipment, while in a conventional mode, to the call control platform. Once the virtual pipe is established, the specialized customer premises equipment operates in a bypass mode such that calls made by the subscriber using the specialized customer premises equipment xe2x80x9cbypassxe2x80x9d the LEC. As long as the virtual pipe exists, the IXC can provide vertical and call control features and functions for incoming and outgoing calls using in-band signaling, while the call control functions typically provided by the customer premises equipment using out-of-band signaling, such as call origination, off-hook, on-hook, and ringing, are provided using in-band signaling. However, conventional out-of-band signaling may still be used to provide conventional LEC features such as call waiting. The virtual pipe to the call control platform may be used for a plurality of calls without being disconnected since the customer premises equipment is prevented from generating a conventional out-of-band mode disconnect signal until breakdown of the virtual pipe is requested by the subscriber. As a result, a subscriber can make one call and pay for one access connection via the LEC and then use that single access connection indefinitely to produce calls across that xe2x80x9cvirtualxe2x80x9d channel.
While the in-band signaling technique described by Schlanger can greatly reduce the amount of access charges paid by the subscriber and long distance carrier, such a technique is disadvantageous in that specialized customer premises equipment is required that must be carried around by the subscriber. Such equipment adds greatly to the cost for the subscriber and is also a very inconvenient way to implement LEC bypass for the subscriber.
The third prior art technique known to the inventor for bypassing the LEC is for the subscriber to lease a T1 line to provide direct switch to switch access to the IXC. However, this approach is prohibitively expensive to all but those companies with very high call volumes sufficient to justify the cost of a T1 line. Leasing a T1 line is quite impractical for companies or individuals with relatively small call volumes where the leasing costs of the T1 line alone would be greater than the amount otherwise paid in originating end access charges.
Accordingly, a LEC bypass technique is desired that does not require specialized customer premises equipment and which is thus more cost competitive. A LEC bypass technique is also desired which extends the benefits of direct T1 access to smaller volume callers without the associated costs of leasing an entire T1 line. The present invention has been designed to meet these great needs in the art.
The present invention meets the above-mentioned needs in the art by providing a LEC bypass technology which does not require the subscriber to purchase any new costly hardware. Instead, the LEC bypass is accomplished utilizing existing network technology within the LEC""s tariffed equipment which effectively permits a plurality of subscribers to share a T1 (DS-1) line for their long distance calling.
In particular, the access charges typically payable by an IXC to a LEC, and, in turn, payable by the subscriber to the IXC, for originating calls are reduced or eliminated by providing a hardwire connection between the IXC and the customer premises. This connection allows a subscriber to xe2x80x9cbypassxe2x80x9d the LEC switching equipment and thus does not require involvement of the local service provider. The hardwire connection is created by purchasing analog data facilities from the LEC which originate at the Central Office. In a preferred embodiment, these facilities are connected directly to a Central Office D4 multiplexer. The voice interface modules typically used in the D4 multiplexer are then replaced by Foreign Exchange Subscriber (FXS) modules which are typically used to interface a customer""s data terminal equipment to T1 or fractional (FT1) services. The terminating end is installed at the subscriber premises and terminated on a standard RJ11X four wire jack. A T1 high capacity digital facility is also ordered from the LEC to terminate to the Central Office D4 multiplexer, and the T1 is D4 /AMI configured for 56 kbps DS0 channels. The terminating end of the T1 is directed to a tandem xe2x80x9ctollxe2x80x9d Central Office and is terminated on a K01 digital electronic cross-connect system (DEXCS) frame which is ordered from the LEC as a reconfigurable data service with customer access. Each of the channels of the T1 is then configured by the customer using the reconfiguration service at the end pointing towards the Central Office D4 multiplexer with Foreign Exchange Office (FXO) Loop Start signaling. A T1 is also ordered from the LEC to connect the DEXCS to the IXC and is also D4/AMI configured for 56 kbps DS0 channels. Each of the channels of this T1 is also configured by the customer using the reconfiguration service at the end pointing towards the IXC with FXS Loop Start signaling. The IXC terminates the T1 within the IXC network and switches the call and performs all required features associated with the call connection in a conventional manner.
In an alternative embodiment, a T3 (DS-3) or higher high capacity digital line may connect the Central Office D4 multiplexer to the DEXCS frame. In such an embodiment, one or more T3:T1 DACCS systems and one or more T3 multiplexers may be used to interface the T1 lines to the T3 lines. Of course, if higher capacity lines were used, higher capacity multiplexers would be required.
In another alternative embodiment, direct analog connections from the customer premises to the DEXCS frame are utilized. In such an embodiment, the DEXCS will accept analog interface cards which are a tariffed service provided by the LEC. The DEXCS is programmed as FXS signaling at the tandem side of the office and FXO to the T1 carrier side. A cross-connect is established to complete the circuit pathway. However, those skilled in the art will appreciate that the cost of such a connection and long-haul analog data lines may be prohibitively expensive.
The hardwire connection implemented by the technique of the invention permits the IXC to connect the calling and called parties without the utilization of an originating end access charge to the LEC and without requiring the calling party to utilize any additional equipment for accessing the service. Instead, the voice connection is made utilizing LEC services which are currently tariffed and available in the continental United States for data services. By placing certain pieces of LEC network equipment in the correct sequence as described herein, analog voice grade service is readily converted to digital high capacity service without payment of an originating end access charge to the LEC for use of the tariffed voice switching equipment. In short, the analog to digital conversion performed at the D4 multiplexer using the FXS modules or at the DEXCS frame in accordance with the invention allows the subscriber to use standard analog telephone sets to access the IXC""s digital network via the lower tariffed data network without having to pass through the LEC""s switching hardware tariffed for voice services.